Cambiamenti climatici e farfalle, online sul Journal of Animal Ecology

Posted on

Un nuovo studio, pubblicato di recente sulla rivista Journal of Animal Ecology, prende in considerazione diversi parametri, caratteristiche ambientali e specie-specifiche, nonché le condizioni climatiche, per valutare i loro possibili effetti sulle dinamiche di popolazione delle farfalle mediterranee.
Allo studio hanno collaborato anche alcuni ricercatori della Divisione ISC del CMCC.

La ricerca ha preso in esame un’area nel Mediterraneo occidentale, importante hotspot di biodiversità con numerose specie di farfalle presenti. Qui come in altre regioni, per far spazio ad agricoltura intensiva e urbanizzazione, nei decenni precedenti si è assistito a un cambio di destinazione d’uso del suolo e a una considerevole riduzione e frammentazione degli habitat naturali. I dati raccolti in 17 anni in 26 diverse località del nord-est della Spagna si riferiscono a 73 specie di farfalle; la premessa alla base dell’analisi è che livelli crescenti di aridità aumentino la probabilità di estinzione/dispersione delle farfalle.

L’identificazione delle variabili ambientali maggiormente responsabili della scomparsa o diffusione delle farfalle permetterà di rafforzare la presenza delle molte specie di farfalle oggi minacciate dai cambiamenti climatici.

Leggi il sommario dell’articolo:

Summary

  • Many species are found today in the form of fragmented populations occupying patches of remnant habitat in human-altered landscapes. The persistence of these population networks requires a balance between extinction and colonization events assumed to be primarily related to patch area and isolation, but the contribution of factors such as the characteristics of patch and matrix habitats, the species’ traits (habitat specialization and dispersal capabilities) and variation in climatic conditions have seldom been evaluated simultaneously.
  • The identification of environmental variables associated with patch occupancy and turnover may be especially useful to enhance the persistence of multiple species under current global change. However, for robust inference on occupancy and related parameters, we must account for detection errors, a commonly overlooked problem that leads to biased estimates and misleading conclusions about population dynamics.
  • Here we provide direct empirical evidence of the effects of different environmental variables on the extinction and colonization rates of a rich butterfly community in the western Mediterranean. The analysis was based on a 17-year dataset containing detection/non-detection data on 73 butterfly species for 26 sites in North-eastern Spain. Using multi-season occupancy models, which take into account species’ detectability, we were able to obtain robust estimates of local extinction and colonization probabilities for each species and test the potential effects of site covariates such as the area of suitable habitat, topographic variability, landscape permeability around the site and climatic variability in aridity conditions.
  • Results revealed a general pattern across species with local habitat composition and landscape features as stronger predictors of occupancy dynamics compared to topography and local aridity. Increasing area of suitable habitat in a site strongly decreased local extinction risks and, for a number of species, both higher amounts of suitable habitat and more permeable landscapes increased colonization rates. Nevertheless, increased topographic variability decreased the extinction risk of bad dispersers, a group of species with significantly lower colonization rates.
  • Our models predicted higher sensitivity of the butterfly assemblages to deterministic changes in habitat features rather than to stochastic weather patterns, with some relationships being clearly dependent on the species’ traits.

Scarica la versione integrale dell’articolo.

Start typing and press Enter to search

Shopping Cart